Streptococcus chenjunshii sp. nov. isolated from feces of Tibetan antelopes.

Abstract

Three Gram-stain-positive, catalase-negative, α-haemolytic, chain-forming and coccus-shaped microorganisms (strains Z15T, Z1 and Z2) were isolated from feces of Tibetan antelopes collected from the Qinghai-Tibet plateau, PR China. The results of 16S rRNA gene sequence studies indicated that Z15T shared 94.5, 93.1 and 92.2\u200a% similarity with Streptococcus pantholopis DSM 102135T, Streptococcus ursoris NUM 1615T and Streptococcus dentapri NUM 1529T, respectively. rpoB and groEL-based sequence analysis of our three novel isolates revealed interspecies divergence of 16.7 and 14.3\u200a% from Streptococcus pantholopis DSM 102135T. The genomic DNA G+C\u2009content of Z15T is 42.48\u2009mol%. Z15T has an average nucleotide identity (ANI) value of 81.19\u200a% with S. pantholopis DSM 102135T and a DNA-DNA relatedness value of less than 70\u200a% in the in-silico DNA-DNA hybridization (isDDH) with other species of genus Streptococcus deposited in the GenBank database. A whole-genome phylogenetic tree based on 246 core genes of 78 genomes of members of the genus Streptococcusindicated that Z15T represents a member of genus Streptococcus but one well separated from the currently recognized species. Z15T contains C18\u200a:\u200a1ω7c (25.5\u200a%), C18\u200a:\u200a1ω9c (19.6\u200a%), C16\u200a:\u200a0 (17.5\u200a%) and C16\u200a:\u200a1ω9c (13.3\u200a%) as its major cellular fatty acids. According to the morphological, biochemical and molecular phylogenetic features of the three novel isolates, they represent a novel species of the genus Streptococcus, and Streptococcus chenjunshii sp. nov. is thus proposed. The type strain is Z15T (=CGMCC 1.16529=DSM 106182).